High temperature x-ray diffraction camera



E. F. CHAMPAYGNE HIGH-TEMPERATURE X-RAY DIFFRACTION CAMERA Aug. 16, 1949.

3 Sheets-Sheet 1 Filed Feb. 3, 1945 INVENTOR iwmcm ATTO R N EY E. F. CHAMPAYGNE HIGH-TEMPERATURE X-RAY DIFFRACTION CAMERA Aug. 16, 1949.

5 Sheets-Sheet 2 Filed Feb. 3, 1945 w iii .MNL.) Tm

, A v ww INVENTOR- M M. mm. A? Wu M Aug; 16, 1949- E. F. CHAMPAYGNE 2,479,471

HIGH-TEMPERATURE X-RAY DIFFRACTI ON CAMERA Filed Feb. 3, 1945 3 Sheets-Sheet 5 ATTORNEY Patented Aug. 16, 1949 ammo s'r r PATENT 2,479,471 H W TEMREEATUBE X-RAY DIFFRACTION QAMERA Edmund F-i Ghampaygne, Noroton Heights,.(.7onn.,

'assignoi; td'Ameri'can Cyanamidfiompany, New;

York. N; Y.,. a. corporation. otMainer hea se s PWL aFJMQl.

.1 Y T e r nt n ent? as es e a were. in which photographs may be taken of the high temperature X-r'aydiffraction'1E{eij;i:eriis oi solid polymorphioinorgain'ic materials frofn one armor pho'us form io'anoprier oeci steiween fractions ofdegrees oizteni perature, and therefore unless the temperatureofthe sample can be"satisf-ac torily co'ntrolied" both from the standpoint of maintenance and change, an inaccurate conch sion as to transition temperatures follows.

' Cameras of this typewliich rely upon reflected heat to raise the' temperature oi the s'a'mple undergoing study necessarily require a considerable input or power and-j the filament used as the sourceof heat is subject to deterioration and consequently has a short l'ife. 4 The principal object of the present invention; is to proyide a camera fon'the. above purposewhich transmits the heat from alsuitab'le source to the sarri'ple by conduction rather than radia tion, as. ithas heen foiind that under these cii' cums'tances, the temperature of a sample may be readily maintained at a'fraction dfa degree for long periods of-tirhe'an-d this: temperature may. be r aised oi lowered? in the same I order; ofimagiiitud accurately and qiiickly.

' "Another important object of the inventiomres sides in the construction of a camera'ofi-the above type which will be of durable material, considering that must operate ati comparativly'hightemperatures, thei iiiaximum of is 615 the order or: 600 G-iiyh-ih'viiill haye no inanufactui} ing difficulties and pe mi of: ready asseiribly: or disssetnhly for 'th aijd'ustment or repair of; parts When-needed. J

To this end the invention contemplates a sampleiholderin good heat conducting contact with a heat transmission barrel rece'fying its heat from an electrical resistance element in close proximity thereto," the heat element being so ar-f ranged; as to minimizeheat loss three-en mas; tion and consequently damage to- "the X -ray photographic se'ns itiye surfiace heldin the usual cylindrical film cassette 'sunrounding the device; 'I fl einv'ention fiuther contrripl ates-thecon'stru ti'on oi the various parts of materials eminently suitable for: the purpose The invention-further includes the novel constmiction, arrangement arfd combination of parts more?' f iillts hereinafter? described and shownin the accompanying drawings in whiting.

i Glairm. (c1. 25.05a.).

Fig. 1 is a side view showing the film. cassette and its relation to the. difiraction. beam. under.

study;

Fig. am asectional elevation ofithe coll'imatings.

tube, sample holderand associated parts show:- mg a preferred electrical hook up;

Fig. 3 is an exploded perspective showing one. method of assemblyoizthe major parts oi Rig; 2;; Fig. 4 is a perspectiveview. ofs a. sampleholdergi' Fig; 5 is a fragmentary sectional View on line; 5--5 of Fig. 42 on anenlargect scale;

Fig. 6: is an exploded perspectiyeyiew. ofrthe.

sample holder; plugiar'idrod usediin forming the,

sample. undergoing. study}.

Fig. 7. is a fragmentary. sectional view; of; a

'sample holder showing a sample. being. flormedg:

Fig. an a similar viewishowingthennex tep;

Fig. 9;is..a similaryiew showing-a iormeisamr. ple; and.

Eig. 1=.0. a. similar; View showin modified;

sample.

Referringv now with particularity to. the, em; bodiment illustrated; an. X-my collimat ns ube. is shown at. 1,.pr ie1ably of, span tone causeote its. reasonable heat resisting anddnsulating; prep 7'. erties as welli as its machinab lity; tube; adaptedto receive at;- he. X-ray en ry end; the; usual restrictordevice, zihayinga telescopin nortionv 3 closely fitting theinsidei oft-the collimating; tubeand provided with a. flange 4;. abutting. the; end. thereof. A lead or...otherwi'se X-ray,. opaque; shield 5; is; located. within the. inner. periphery ofe the telescoping portion 3. and the. fiace Of-thE-IIGJr stricter 2. and. the lead. shield 5; are provided. with primary and secondary restricting apertures. bf

' and'l respectively. is usual in devi'oesofithis character, the secondary aperture I isfco axial With' the primary. aperture 6. and slightly. larger in diameter in ordei'Yt'o transmit therethrdugli parallel 'X-rays entering the aperture Bi with minimum scattering.

The openeridof-the collimating tube I is provided with a bell shaped extension! oyerlying thee nd portionfi or: a heat transmission barrel l 0 preferahly of stainless" steel and provided with? a terminal annular outwardly 'projecting fiang e; I I As shown, the endof the barrel II! "extends: telescopically within the bell l l' of, the c oll irn ing tube 'in-a loose'fitwith an expansion'elenient between the collimating tube and thej'heatltrans-j mission barrel which may coriye niently take the, form of aspring 'lfof coilediiichiioriie Wire oif the like.

Barrel l 0 is provided with a raised threaded. portion I S to 'receiyethe interiorlythreaded' ring I 4, preferably of stainles sistelor the lilie which is secured as by 'machine'screws i5 wages nular transite collar H3; having a projecting s g As shown, the inwardly projecting flange fl= 3 on the collar l6 abuts and engages the flange H on the bell of the collimating tube l which also holds the end 9 of the heat transmission barrel I against the expansion spring |2 upon proper relative movement between the barrel l8 and the threaded ring I4.

The main body of the barrel It) may be wrapped with a layer l9 of electrical insulation such as mica or asbestos upon which is wound an electrical resistance element of a size and extent sufiicient to raise and maintain the sample at a desired temperature, say up to 600 C. The ends of the resistance element 20 are connected through electrical leads 2| through a variable voltage transformer 22 stepped down to about twenty-five volts, a bleeder resistance element 23 for maintaining the temperature of the sample within close limits after the desired temperature has been reached, and an external relay 24 to a potentiometer controller 25 to which an E. M. F. from a 115 volt A. C. source is flowed by means of leads 26 through proper manipulation of switch 21. Thus any degree of heat may be obtained, maintained, and adjusted within the limit of the heating elements which limit may conveniently be approximately 600 C. Obviously, a device may be constructed to obtain higher or lower temperatures as desired by merely changing the type of heating element and/or the character of the E. M. F. supplied thereto.

Insulation 2B is provided for embedding the resistance wires 20 and to prevent loss of heat in a radial or outward direction. This insulation may take the form of powdered or flaked asbestos although preferably it consists of a set packing of flrebrick cement. In order to confine the insulation, transite washers 29 and 36 are provided, the latter being of a greater radial extent than the former so as to abut and hold in place an aluminum housing 3| held between the washer 30 and the flange H of the transite collar I6. Thus the washer 29 and the housing 3! may serve as forms during the packing of the insulation material 28 after which the washer 3E! may be put in place. It is preferable that the inner surface of the aluminum housing 3| be polished or a supplemental reflector 3|a provided so as to reflect any heat reaching it from the inside back into the device.

A cylindrical restrictor 32, preferably of stainless steel, having a restricting aperture 33 and engaged against an annular shoulder 34 machined on the inside of the barrel l0.

A metallic sample holder is shown at 35 preferably of stainless steel having cylindrical portion 36 telescopically and closely engaging the inside of the barrel in good heat conduction contact therewith. As shown the end of the cylindrical portion 36 of the sample holder abuts the guard 32 and holds the latter in fixed position. The sample holder is also provided with an outwardly projecting flange 3'! abutting the end of the barrel iii. The sample holder is also provided with an aperture 38 in which the sample undergoing study through its diffraction pattern may be mounted. It is, of course, important that the apertures 6, 1, 33 and 38 be co-axial and arranged for the transmission therethrough of parallel X-ray beams from any suitable source (not shown).

An aluminum cap 39 having shoulder 48 is fitted over the end of the device so that the shoulder engages the edge portion of the washer 30 and an enlarged cylindrical portion 4| overlies the housing 3| in a close frictional fit. The cap 39 is provided with a radial slot 42, the upper 4 end of which is coincident with a horizontal line drawn outwardly from the upper inside surface of the sample receiving aperture 38, and the other end of the slot is coincident with a vertical line drawn downwardly and across the outer face 43 of the sample holder.

A thermocouple well 44 is provided in the sample holder as close to the sample receiving aperture 38 as possible and a thermocouple 45 is located therein and provided with leads 46 which pass through apertures in the transite washer 30 preferably through tube 41 embedded in the insulation 28 and suitable apertures in the washer 29, ring l4 and collar "5. These leads are then properly connected to the potentiometer controller as is usual in such cases. As thus arranged the thermocouple and its leads may be readily removed for replacement or repair without disturbing the other parts with the exception of the removal of the aluminum cap 39.

In assembling the collimating tube and the parts within the housing 3| and cap 39, the following procedure may be used:

The collar I6 is slipped over the left-hand end of the collimating tube until the flanges l1 and ll abut, the expansion spring i2 is put in place, the barrel l0 inserted and the ring I4 threaded onto the barrel against the collar until the apertures through which the leads 2| of the resistance element 29 pass are in alignment. The machine screws |5 are then put in place to secure the collar I6 and the ring l4 together. Proper rotation of the barrel ID will then cause the flanges and H to be in close engagement against the tension of the spring l2. The washer 29 is then slipped over the barrel from the right-hand end thereof until it abuts the ring I4 and the apertures for the leads 2| to the resistance 20 are in proper alignment. The mica or asbestos wrapping for the barrel is then put in place and the resistance 20 assembled so that its leads 2| pass through the aligned apertures in the washer 29, ring l4 and collar I6; The housing 3| is then slipped over the washer 29 and the ring l4 so that its end abuts the flange H on the collar It. The insulating packing 28 is then put in place and closed by the washer 30.

Following this operation the restrictor 32 is inserted inside of the barrel |0,'the sample holder tube assembly and the film cassette.

35 containing its prepared sample inserted in the end of the barrel until the flange 31 of the former engages the end of the latter, the thermocouple 45 placed into its well and its leads 46 passed through the washer 30, the tube 41 and aligned aperturesin washer 29, ring l4 and collar l6 and properly connected to the potentiometer controller 25. The aluminum cap 39 is then placed in position so that the slot 42 is in the proper location to permit projection of the diffraction pattern of the sample in the aperture 38 upon the film.

Fig. 1 shows the general relationship between the X-ray tube stack, the source of X-ray radiation, the sample holder, heater and collimating In this figure the stack is shown at 48 which is of conventional design housing, a usual source of X-ray radiations which are projected through the collimating tube I held in an annular hub 49 as by set screw 59. The hub is a part of the standard and well known cylindrical film cassette indicated generally at 5| which is provided with the usual cyclindrically arranged X-ray sensitive surface.

The assembly including the aluminum housing 3| is so arranged within the film cassette that a portion of the axis of the cassette lies in the plane of the outer face 43 of the sample holder, the parts being so positioned that the diffracted X-ray pattern projected through the slot 42 in the cap 39 extends through the 90 degree are 52 onto the film in the cassette. As usual, the zero beam is caught within a well 53 mounted on the cassette the bottom of which is made of X-ray opaque material so as to provide minimum interference between the zero beam and the useful diffracted beam to be studied.

Where the sample of material undergoing study and held in aperture 38 is subject to change due to oxidation or reduction, it may be desirable to maintain it in an atmosphere of either an inert, reducing or oxidizing gas as the case may be. In such cases, a gas inlet 54 in the wall of the collimating tube may be provided and a gas outlet 55 in the sample holder through which a gas of any desired character may be passed.

In the investigation of polymorphic powder or crystals of inorganic materials through study of their X-ray diffraction patterns at high temperature, it is desirable that a sample be mounted in the sample holder in such a, way as will insure the production of a sharp diffraction pattern brought about by the use of as thin a sample as possible. Two preferred modes of mounting a sample are shown in Figs. 9 and 10.

In one form, a plug 56 having axially projecting stud 51 is inserted inside of the sample holder 35 so that the stud projects within the sample receiving aperture 38 a desired distance. The top of this stud may be fiat as at 58 or it may be convex as at 59, dependent upon the desired shape to be given to the back side of the final specimen mounted in the aperture 38. In either event, a portion 60 of the material undergoing investigation is placed on the sample holder 35 in a quantity sufficient to more than fill the remaining portion of the aperture 38 and smoothed off as by spatula 6|. Then while retaining the plug 56 and its stud 51 in place, a rod 62 having a knurled finger grip 63 and a convex end 64 is impressed into the loose powder 65 with oscillation so as to form a concavity 66 due to the curvature of the end 64. This then leaves the final sample as shown at 81 in Fig. 9 upon removal of the plug 56. It is desirable, of course, that the smallest thickness dimension of the sample 61 be such that a sharp diffraction pattern may be obtained.

In .order to render adequate strength to the bridged sample thus produced and to prevent its accidental displacement during handling incident to mounting in the complete device it may be desirable to use a plug 56 having a stud with a convex face 59 thereon. Under these circumstances and manipulating the loose sample as before a bridged sample 68 is produced which is concave on each side. This type of bridged sample is stronger than the sample 61 as a supporting arch is formed on each side thereof.

Having thus formed a sample, it only becomes necessary to insert the sample holder 35 into the end of the heat transmission barrel ID of the assembly and proceed as before.

This application is related to applicant's copending application Serial No. 576,092.

While the invention has been described with particular reference to specific embodiments, it is to be understood that it is not to be limited thereto but is to be construed broadly and restricted solely by the scope of the appended claim.

What is claimed is:

In a high temperature X-ray diffraction camera including a metal sample holder having a sample receiving aperture and an outer face, a metal heat transmission barrel in heat conduction contact therewith, a heating element in proximity to the heat transmission barrel and insulated against outward heat radiation in a radial direction, and an X-ray collimating tube co-axial with the heat transmission barrel and the sample holding aperture in the sample holder and means to pass a gas through the collimating tube, heat transmitting barrel and sample'holder.

EDMUND F. CHAMPAYGNE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,546,349 Hull July 14, 1925 2,341,108 McLachlan Feb. 8, 1944 OTHER REFERENCES Structure of Metals, Barrett, published by McGraw-Hill Book Co., Inc. New York, N. Y., 1943, pp. 119-120.

Journal of Applied Physics, vol. 14 (Mar. 1943), page 137. 

